Most operating systems provide program interfaces for performing
operations involving the sending and receiving of data over sockets. Most
operating systems also provide administrative capabilities to control the
amount of memory allocated per socket that is used as data buffers.
Before you begin
Check your operating system settings that are relevant
to TCP sockets. For example, if you are using an AIX operating system, check
the values that are specified for the tcp_sendspace, tcp_recvspace, and sb_max
settings. Similarly on a Linux operating system, check the values that are
specified for the tcp_rmem, and tcp_wmem settings.
- Use the WebSphere Application Server performance monitoring infrastructure
to determine the average message size that the core group transport handles.
If your operating system setting for the default buffer size is smaller than
the average message size, make one of the following changes:
- Change the default buffer size setting for your operating system. However,
this action might be inappropriate because it might affect the operation of
other applications running on this operating system.
- Change the size of the socket buffer that the core group transport obtains.
The value that is specified for the IBM_CS_SOCKET_BUFFER_SIZE core group custom
property determines the size of the socket buffer that the core group transport
obtains. The following table shows the relationship between the values that
can be specified for this property and the underlying memory allocation size
per socket buffer type:
Socket Buffer Type |
Property set to 0 |
Property set to 1 |
Property set to 2 |
Property set to 3 |
Unicast receive |
Operating system default buffer size is used. |
Buffer size is 64 kilobytes |
Buffer size is 256 kilobytes |
Buffer size is 1 megabyte |
Unicast send |
Operating system default buffer size is used. |
Operating system default buffer size is used. |
Buffer size is 64 kilobytes |
Buffer size is 128 kilobytes |
Multicast receive |
Operating system default buffer size is used. |
Buffer size is 512 kilobytes |
Buffer size is 1 megabyte |
Buffer size is 3 megabytes |
About this task
You might want to change the size of your core group buffers in the
following circumstances:
- You are directed to do so by IBM Support
- You are directed to do so during the course of installing another WebSphere
product.
- You want to change the behavior of the core group transport without affecting
the behavior of other sockets.
- You are trying to tune the network communication path of your system to
your application.
To change the socket buffer space that the core group transport allocates:
Procedure
- In the administrative console, click Servers > Core groups >
Core group settings > core_group_name.
- Under Additional Properties, click Custom Properties.
- Change the value that is specified for the IBM_CS_SOCKET_BUFFER_SIZE
custom property.
If the IBM_CS_SOCKET_BUFFER_SIZE property already
exists, click the property name and specify either 0, 1, 2,
or 3.
If this property does not already exist, click New and
create it:
- In the Name field, specify IBM_CS_SOCKET_BUFFER_SIZE.
- In the Value field specify one of the following strings:
- Click OK, and then click Save to
save your changes.
- Select Synchronize changes with nodes,
and then click Save again.
- Restart all members of the core group.
Results
After the servers restart, the core group members all run with the
new socket buffer size settings.